Use of a Broken or Risky Cryptographic Algorithm (CWE-327) in libcurl

## Summary: The DES cipher (Data Encryption Standard) is used in the `curl_ntlm_core.c` file of libcurl. DES is considered insecure due to its short key length (56 bits) and its susceptibility to brute-force attacks. Modern cryptographic standards recommend replacing DES with AES (Advanced Encryption Standard), which is more robust and secure. ## Affected version [Which curl/libcurl version are you using to reproduce? On which platform? `curl -V` typically generates good output to include] ## Steps To Reproduce: 1. Inspect the `lib/curl_ntlm_core.c` file of the libcurl source code. 2. Locate the use of the `kCCAlgorithmDES` constant, which corresponds to the DES cipher. 3. Verify that DES is being used for cryptographic operations in NTLM authentication (NTLMv1). ## Supporting Material/References: - File: `lib/curl_ntlm_core.c` - Line Reference: 228:29 - CWE Reference: [CWE-327](https://cwe.mitre.org/data/definitions/327.html) * [attachment / reference] ## Impact ## Summary: Using DES compromises the security of the application due to the following points: - **Brute-force attacks**: The short key length makes it possible to brute-force DES keys in a reasonable amount of time with modern hardware. - **Cryptographic weaknesses**: DES is vulnerable to various cryptanalysis techniques, such as differential and linear cryptanalysis. - **Compliance risks**: DES does not meet modern cryptographic standards and could lead to non-compliance with security regulations. An attacker exploiting this vulnerability could: - Intercept and decrypt sensitive data during NTLM authentication. - Execute man-in-the-middle (MITM) attacks to impersonate a user or server. - Gain unauthorized access to systems relying on NTLM authentication. --- ## Recommended Fix: Replace the use of `kCCAlgorithmDES` with `kCCAlgorithmAES`, which supports stronger encryption standards (e.g., AES-128, AES-256). This change will significantly enhance the security of NTLM authentication in libcurl.